Dump body leverage



Dec. 13, 1938. F. BlszANTz DUMP BODY LEVERAGE Filed June 24, 1957 Dec. 13, 1938. F.2Bxsz'ANTz 2,139,794

' yDUMP BODY LEVERAGE Filed June 24, 1937 2 sheets-sheet 2 ATTORNEY.

Patented Dec. 13, 1938 UNiTEo stares ATENT OFFECE DUMP sony paysages.

Application June 24,

'7 Claims.

This invention relates to dump bodies and, in particular, to dump body lift mechanisms.

It is an object of this invention to provide a dump' body leverage which is simple in construction, extremely eiiicient in operation, which is strong and light in weight, and which is extremely compact.

It is a further object of this invention to provide a leverage for use in dump trucks, by means of which a simple leverage construction is utilized to progressively, during operation, alter or modify the mechanical advantage of the mechanism, or the effective lever arm thereof through which lifting force is applied in such manner as toapply a relatively great initial lifting force at relatively low lifting speed and automatically to increase the lifting speed progressively during .the lifting operation when it becomes unnecessary, due to shift of weight, to maintain such a large lifting force as was initially applied.

It is a further object of this invention to provide a dump body leverage mechanism including a system of members including cooperating lifting arms and lifting brackets provided with cooperating rack and gear means adapted initially to provide a relatively large effective lever arm which is progressively decreased during a lifting operation to progressively increase the speed of lift.

It is a further object of this invention to provide such a mechanism wherein, by utilizing a leverage providing a varying mechanical advantage throughout the lifting operation, which corresponds to variation in load required to be lifted, a relatively small lifting force Imay be utilized to efficiently lift an extremely large load at progressively increasing sp-eed.

It is a further object of this invention to provide such structure wherein a hydraulic motor means of comparatively low power may be utilized.

These and other objects and advantages will appear from the following description taken in connection with the drawings.

AIn the drawings:

Figure l is a fragmentary side elevational view, partly broken away, of a preferred embodiment of this invention, as applied to the dump body of a truck;

vFigure 2 is a top vplan View of the lifting or leverage Amechanism illustrated in Figure l;

vFigure 3 is a section taken on the line 3 3 of Figure k2;

Figure 4 is a section taken on the line i4 of Figure 2;

1937, ASerial No. 150,155

Figure 5 is a section taken on the line 5--5 of Figure 2; and

Figure 6 is a View similar to Figure 5, but illustrating a modification of the structure illustrated therein, wherein a single sprocket wheel is'subf5V stituted for the pair of sprocket wheels illustrated in Figures l to 5 inclusive.

Referring to the drawings in detail, in which the structure cf this invention has been illustrated as applied to a known form of dump body, l0 l have shown, in Figure 1, atruck chassis frame designated l, which is provided with suitable pivots 2, upon which are pivotally mounted the side brackets 3 of the truck body li. Rigidly secured to the chassis frame l, in any suitable 4l5 manner, is a lift frame, generally designated 5, which comprises a rear transverse frame member 6 of angle form, a forward transverse frame member l of angle form and a plurality of longitudinal spaced frame plates which are ar- 20 ranged in spaced pairs to accommodate the lift mechanism, as will hereinafter more clearly appear.

At their rear ends, the longitudinal frame plates 8 are provided with aligned apertures 25 through which extends the transverse pivot rod 9 which is journaled in the tubular spacer l0 having each end thereof rigidly secured to `a central longitudinal frame plate 8, and which transverse pivot rod has pivotally secured there- 30 to, between each exterior spaced pair of longitudinal frame plates S, a tubular lifting arm support il. The lifting arms are each generally designated l2 and, in the embodiment illustrated, a pair of lifting arms is provided, one 35 adjacent each side of the dump body d. Each lifting arm comprises a pair of spaced parallel side plates I3 which are substantially triangular, each pair of which is connected at its rear end by the corresponding tubular lifting arm support il which is rigidly secured thereto, as described above.

Throughout a substantial portion of their lengths, the side plates are secured in spaced relation by means of the pintle members Ill which are beaded over at each end and which support v the tubular members l5 which are disposed between the plates and which may be rigidly secured to the pintle pins lll and/or spaced parallel side plates I3 or mounted for free rota- 50 tion on the pintle pins i4. The tubular members l5, therefore, form bearing members which may be either stationary or freely rotatable on the pintle pins I4, as pointed out above. While the pintle pins i4 and supported bearing ,members g5 I5 may, if desired, be arranged in a straight line substantially parallel to the lower edge of the side plates I3, they are preferably arranged, as illustrated particularly in Figures 1, 3 and 4, in a path having a substantially arcuate or undulatory portion. Each side plate I3 is provided with a guide rail member I5 rigidly secured thereto in any suitable manner as by means of screws or rivets I'i. The lower surface of each guide rail I5 is parallel to the corresponding trackway or rack formed by the bearing members I5, and at the forward end of each guide rail I5 is a downwardly directed projection i8 which is adapted to operate as stop means, as will be hereinafter more clearly explained. The spaced bearing members I5 thus form, with the guide rails I5, a trackway in the form of an antifriction rack which is preferably curved, as shown in Figures 1, 3 and 4. Each side plate I3 is provided, adjacent its forward upper apex, with an aperture pivotally receiving the cross-head pivot rod i9 which extends therethrough, as shown in Figure 2.

Supported by the crosshead pivot rod I9, between each pair of side plates i3, is a spacer 20 having each end thereof secured to one of the side plates I 3 in such manner as to form a means for securing to the upper rear portions thereof rigidly in spaced relation. Pivotally supported on thecrosshead pivot rod i3, between the lifting arms, is a crosshead'l having thereon an extension 22 adapted for rigid connection with the piston rod 2,3 of the iiuid motor generally designated 24. The cylinder 25 (which includes a conventional piston secured to the end of the piston rod 23) is provided at its forward and lower ends with a pair of pivot brackets 23 :formed integrally therewith or rigidly attached thereto. Thepivot brackets 26 are provided with aligned apertures, through which extends the pintle member 21 having each end thereof supported Vin a pintle bracket 28 rigidly secured to the forward cross member or angle 'I of the lift frame 5.

When uid pressure is released from the fluid motor 24, the dump body Il takes a Vhorizontal position, as illustrated in Figure 1,'wherein the lower edges. of the lifting arms I2 are substantially horizontal. When iiuid pressure is introduced to the cylinder 25 of the fluid motor 24, the piston rod 23 is thrust rearwardly or to the right, as seen in Figures 1, 3 and 4, to swingl the lifting arms I2 in clockwise direction about the transverse pivot rod 9, whereupon the parts take the position illustrated in dash lines in Figure '1. Upon release of fluid pressure from the cylinder 25 of the uid motor 24, the parts will again assume the position illustrated in full lines in Figure l.

VIt is, of course, to be understood that any suitable source of iiuid pressure may be provided for operating the dump body lift mechanism and the preferred source of iiuid pressure comprises a suitable iiuid pump and reservoir mounted upon the chassis frame l with the pump capable of connection, for operation, to the source of motive power of the Vvehicle having the chassis I.

Rigidly secured to the under side of the dump body 4 is a pair of lifting or thrust brackets, generally designated 33, which, in the form illustrated in Figures 1 to 5 inclusive, comprises a pair of bracket plates 3i which are substantially vertically disposed and each of which is provided at its upper end with a transverse flange 32 which is adapted for attachment to the under side of the dump body 4. The bracket plates 3| are provided at their lower ends with aligned apertures adapted to receive the pintle member 33 which is surrounded by the spacer 34 which is disposed between the bracket plates 3l and which has each end secured rigidly to one of the bracket plates 3 I.

Rotatable on the pintle 33 at each side of each bracket plate 3i and disposed between each bracket plate 3! and. a corresponding side plate I3 is a rotatable collar 35 having rigidly secured thereto a pinion or sprocket member 36. 'Ihe teeth of the pinion or sprocket members 36 engage the tubular bearing members i5, as shown in Figures 1, 3 and 4, and the sprocket or pinion member 36 thus cooperates with the bearing members I5 to form, in effect, a rack and pinion.

The collars 35 which are rigid with the pinion Y or sprocket members 36 cooperate with the lower edge of the corresponding guide rail I5 to retain the pinion or sprocket members 33 in engagement with the bearing members I5.` The upper end portions of the bracket plates 3I are secured together in spaced relation by theinterposed spacer collars 37 and the bolts 38 which extend therethrough. The flanges 32 of the bracket plates 3i may be bolted, welded or otherwise rigidly secured to the lower surface of the dump body 4.

1n the modification illustrated in Figure 6, the spacing collars 37 and bolts 38 are of substantially greater length than in the form illustrated in Figures 1 to 5 inclusive and, instead of the pair of pinion members 35, a single pinion mem,- ber 33 of substantially greater width than the pinion members 35 is interposed between the bracket plates 3i, being' attachedv rigidly to the bearing collar 43 which is rotatably supported by the pintle 33. Rotatably mounted on each end portion of the pintle 33, between each bracket plate 3l and the corresponding side piate I3 is a bearing collar 4l adapted to cooperate with the corresponding guide rail I6 to retain the sprocket member 33 in engagement with the trackway or rack formed by the tubular members I5.

Attention is particularly directed to the fact that, when the trackway formed by the bearing members I5, is provided with a curved portion, as illustrated in Figures 1, 3 and 4, the action of the lifting arms l 2 is modified when compared toy the situation existing when the trackway or rack formed by the members I5 is straight. In the latter case, when the rack or trackway is straight, the effectivel lever arm through which force is applied through piston rod 23 is progressively increased, while the parts ae moving from the position illustrated in Figure 1 in full lines to that illustrated in that figure in dash lines. The eiective lever arm is at rst relatively small and progressively increases as the body 4 is inclined. Therefore, as the eifective lever arm is initially slight and progressively increases with the angle of lift, the initial effective lifting force applied is substantially great and is progressively decreased during the lifting o-pbraticn, while the speed of lift is progressively increased from minimum to maximum, when the parts move from the position illustrated in full lines tothe position illustrated in, dash lines in Figure l.

When the rackway or trackway formed by the bearing members I5 is provided with a curved portion, as illustrated in. Figures 1, 3 and 4, an additive dierential effect is achieved, wherein the speed of lift and the effective lever arm increase progressively at an uneven rate which is at times greater and at times less than the rate of increase Where the rackvvay or trackvvay is straight. In other Words, When force is applied through the crosshead pivot rod I9, as seen in Figure 3, the lifting arms I2 are swung to the right about the pivot rod 9 and the pinions 36 travel to the rear or leftvvardly of the trackvvay formed by bearing members I5. The inclination of the four rearmost or rightmost bearing members I5 from the horizontal causes the increase in effective lever arm to be less than would occur if the trackvvay Were straight. As soon, however, as the pinions engage and pass the fourth bearing member I5, the trackvvay formed by the fifth, sixth and seventh bearing members I5, Which is inclined, increases the rate of speed of the effective lever arm and the angular speed of lift; and, when the foremost, last, or leftward four bearing members I5 are being traversed by the sprocket members 36, the speed of lift and the effective lever arm, through which force is applied, are progressively increased at a uniform rate. Thus, upon application of lifting force through crosshead pivot rod I9, the maximum force is initially applied through the least effective lever arm, and the increase of effective lever arm is retarded by the inclination provided at the rst part of the trackvvay and then increased until the straight portion of the trackvvay is reached, at which time the increase in elective lever arm and the increase of lifting speed will occur at aconstant rate.

It is, of course, to be understood that the trackvvay or rackvray formed by the bearing members I5 may be substantially varied and made either straight or arcuate and that the acuteness of the arcuate portions thereof may be varied as desired.

It will be further understood that the above described structure is merely illustrative of the manner in Which the principles of my invention may be utilized and that I desire to comprehend Within my invention such modifications as come within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. In leverage mechanism for a dump truck, a hoist frame adapted to be rigidly secured to a truck chassis, a lifting bracket adapted to be rigidly secured to the under side of a dump body pivoted on said truck chassis, a sprocket on said lifting bracket, a. lifting arm pivoted on said hoist frame, a rackvvay on said lifting arm co-mprising spaced pin means adapted to support said sprocket, and means supported by said hoist frame to apply tilting force to said lifting arm.

2. In leverage mechanism for a dump truck, a hoist frame adapted to be rigidly secured to a truck chassis, a lifting bracket adapted to be rigidly secured to the under side of a dump body pivoted onv said truck chassis, a sprocketl on1 said lifting bracket, a lifting arm pivoted on` said hoist frame, a curved rackvvay on said lifting arm comprising spaced pin means adapted to support said sprocket, and means supported by said hoist frame to apply tilting force to said lifting arm.

3. In lifting means adapted for use in a dump truck including a chassis frame and a dump body pivotally mounted thereon, a bracket arm having sprocket means thereon and adapted to be secured to the dump body, and a lifting arm adapted to be pivotally supported on. said chassis frame and having thereon a trackWay comprising a plurality of spaced pins adapted to support said sprocket.

4. In lifting means adapted for use in a dump truck including a chassis frame and a dump body pivotally mounted thereon, a bracket arm having sprocket means thereon and adapted to be secured to the dump body, and a lifting arm adapted to be pivotally supported on said chassis frame and having thereon a curved trackvvay comprising a plurality of spaced pins adapted to support said sprocket.

5. I n lifting means adapted for use in a dump truck including a chassis frame and a dump body pivotally mounted thereon, a. bracket arm having sprocket means thereon and adap-ted to be secured to the dump body, a lifting arm adapted to be pivotally supported on said chassis frame and having thereon a trackway comprising a plurality of spaced pins adapted to support said sprocket, and means on said lifting arm adapted to retain said sprocket in engagement With said trackway.

6. In lifting means adapted for use in a dumpy truck including a chassis frame and a dump body pivotally mounted thereon, a bracket arm having sprocket means thereon and adapted to be secured to the dump body, a lifting arm adapted to be pivotally supported on said chassis frame and having thereon a trackway comprising a plurality of spaced pins adapted to support said sprocket, and means on said lifting arm adapted to retain said sprocket in engagement With said trackway and to limit swingable movement of said lifting arm in one direction.

7. In lifting means adapted for use in a dump truck including a chassis frame and a dump body pivotally mounted thereon, a bracket arm having sprocket means thereon and adapted to be secured to the dump body, a lifting arm adapted to be pivotally supported on vsaid chassis frame and having thereon a curved trackway comprising a plurality of spaced pins adapted to support said sprocket, and means on said lifting arm adapted to retain said sprocket in engagement with said trackway and to limit swingable movement of said lifting arm in one direction.

FRED BISZANTZ. 

